British scientists begin a new study on Tuesday to consider how human DNA is used in animal experiments and to determine what the boundaries of such controversial science might be.

Though experts have been swapping human and animal DNA for years - like replacing animal genes with human genes or growing human organs in animals - scientists at the Academy of Medical Sciences want to make sure the public is aware of what is happening in laboratories before proceeding further.

"It sounds yucky, but it may be well worth doing if it's going to lead to a cure for something horrible," said Robin Lovell-Badge, a stem cell expert at Britain's National Institute for Medical Research, and a member of the group conducting the study.

If life is to be found beyond our home planet, then our closest encounters with it may come in the dark abyss of some extraterrestrial sea. For Earth is certainly not the only ocean-girdled world in our solar system. As many as five moons of Jupiter and Saturn are now thought to hide seas beneath their icy crusts.

To find out more about these worlds and their hidden oceans, two ambitious voyages are now taking shape. About a decade from now, if all goes to plan, the first mission will send a pair of probes to explore Jupiter's satellites. They will concentrate on giant Ganymede and pale Europa, gauging the depths of the oceans that almost certainly lie within them.

A few years later, an even more audacious mission will head towards Saturn to sniff the polar sea spray of its snow-white moon Enceladus. It will also visit Titan, which has perhaps the most astonishing extraterrestrial landscape in our solar system. To explore this giant moon, the spacecraft will send out two seemingly antique contraptions: a hot-air balloon to fly over the deserts and mountains, and a boat that will float on a sea of liquid hydrocarbons.

This plan for ocean exploration was announced in February, when the science chiefs of NASA and the European Space Agency decided to press ahead with the planning stages of both missions. Jupiter is the destination that tops the schedule, probably because the Europa Jupiter System Mission relies on well-tested space technology. The plan is for EJSM to lift off in early 2020, in two pieces. NASA's contribution, the Jupiter Europa Orbiter (JEO), and ESA's Jupiter Ganymede Orbiter (JGO) will be launched within a month of each other and plot parallel courses for Jupiter, arriving after six years. They will then engage in a complex dance, visiting various moons before each probe homes in on its prime target.

The collision of a large extraterrestrial object with Earth almost 2 billion years ago may have stirred the seas worldwide and delivered a huge serving of oxygen to the deep ocean.

The Sudbury impact, named after the Canadian city located near the center of what remains of the ancient crater, happened around 1.85 billion years ago (SN: 6/15/02, p. 378). Despite erosion since then, the impact structure - at least 200 kilometers across - is recognized to be the second-largest on the face of the planet, says William Cannon, a geologist with the U.S. Geological Survey in Reston, Va., and coauthor on a paper in the November Geology. The event fundamentally affected the concentrations of dissolved oxygen in the deep sea - enough to almost instantly shut down the accumulation of marine sediments known as banded iron formations, report Cannon and coauthor John F. Slack, also of the USGS in Reston.

Banded iron formations, massive deposits rich in iron oxides, have accumulated at several periods in Earth's long-distant geological past, mostly when atmospheric concentrations of oxygen were low (SN: 6/20/09, p. 24).

A group of engineers working on a novel manufacturing technique at NASA's Langley Research Center in Hampton, Va., have come up with a new twist on the popular old saying about dreaming and doing: "If you can slice it, we can build it."

That's because layers mean everything to the environmentally-friendly construction process called Electron Beam Freeform Fabrication, or EBF3, and its operation sounds like something straight out of science fiction.

"You start with a drawing of the part you want to build, you push a button, and out comes the part," said Karen Taminger, the technology lead for the Virginia-based research project that is part of NASA's Fundamental Aeronautics Program.

She admits that, on the surface, EBF3 reminds many people of a Star Trek replicator in which, for example, Captain Picard announces out loud, "Tea, Earl Grey, hot." Then there is a brief hum, a flash of light and the stimulating drink appears from a nook in the wall.

Witness the yellow- and black-striped swarm buzzing around Daren Eiri as he works, and you wouldn't think honeybees are in short supply. Dozens of fuzzy, winged insects blanket a grapefruit-sized glass dish in Eiri's hand one warm afternoon at UCSD's Biology Field Station.

"I used to hate doing this," said Eiri, a University of California, San Diego graduate student, who at the moment is a perch for honeybees occasionally landing to lick sugar from his skin. "When they're feeding I'm pretty sure they're only concerned with food." Eiri puts a squat cup of sweet liquid on top of the plate and sets the feeder inside a wooden tunnel.

But this bee-rich environment is deceptive: Eiri and the James Nieh Bee Lab at UCSD are researching a serious but poorly understood phenomenon known as Colony Collapse Disorder. Despite the bees flying like popcorn up and down Eiri's carefully constructed passageway, these pollinators are perishing at an unprecedented rate in the United States and the world.